RESUMEN
Tetrathiafulvalene-p-chloranil exhibits photoinduced phase transition (PIPT) between neutral (N) and ionic (I) phases, in which the constituent molecules are approximately charge-neutral and ionic, respectively. In addition to visible-light irradiation, which can induce both N â I and I â N PIPTs, infrared irradiation has been reported to induce the N â I PIPT. These results suggest that N â I and I â N PIPTs can be driven by electronic excitation, and the I â N PIPT can also be driven by vibrational excitation. However, the feasibility of the N â I PIPT using vibrational excitation remains an open question. In this study, we address this issue by simulating the PIPT processes using a nonadiabatic molecular dynamics approach combined with real-time electron dynamics at the level of a semiempirical quantum chemical model, density-functional tight binding. The results show the importance of vibronic interactions in the PIPT processes, thereby suggesting the possibility of N â I PIPT by vibrational excitations with infrared irradiation.